1. Field of the Invention
The present invention relates to an apparatus and method for lifting, moving and positioning a workpiece. In particular, it relates to a device and method for lifting a circumferential heater used in the manufacture of silicon ingots by the Czochralski method.
2. Description of the Prior Art
Traditionally, devices used to lift circumferential heaters used in the manufacture of silicon ingots are lowered around the outside edge of the heater. Slider bars are then inserted under the heater, and secured to the lifter. In some instances, a cage is then placed around the heater. Prior devices required an operator to manually place support plates under the heater, attach a cage to the supports, and then attach this apparatus to a lifting device. The heater could then be lifted from the bottom chamber of a Czochralski-type crystal puller machine for machine cleaning or heater replacement. These same devices are also used to place a new heater in the puller machine.
The above device, and similar devices, are appropriate for silicon manufacturing operations. However, they have a number of parts that must be assembled prior to and during the lifting, thereby consuming operator and machine time. This assembly and disassembly results in metal-to-metal contact among the device's parts, within the assembly, potentially damaging the device. Additionally, heat transfer from the heater the lifter, resulting from contact between the heater and the lifter, can cause the lifter to warp, leading to the added cost and time of replacement parts; it also increases the temperature of the lifter, thereby requiring a cooling period before the lifter can be handled.